Cfrgtkky

Unfortunately, I have a lot of TeX code which should look different that it does not, but I cannot modify its code body. However, I can modify the preamble and for example, I have learned that I can redefine texttt to make every

texttt{text}

into

colorbox{shadecolor}{texttt{text}}

by running

letoldtexttttexttt

renewcommand{texttt}[1]{colorbox{shadecolor}{oldtexttt{#1}}}

in the preamble. That might not be perfect, but it works great. However, now I want to put every verbatim environment inside a Shaded environment. Obviously I cannot use renewcommand for this again. Is there something else I can use to make every

begin{verbatim}

text

end{verbatim}

into

begin{Shaded}

begin{verbatim}

text

end{verbatim}

end{Shaded}

by changing the preamble only?

Screenshots:

What it looks like:

What it should look like:

MCVE:

documentclass[12pt]{article}

usepackage{xcolor}

usepackage{framed}



definecolor{shadecolor}{RGB}{200,200,0}

newenvironment{Shaded}{begin{snugshade}}{end{snugshade}}



begin{document}



begin{verbatim}

text

end{verbatim}



end{document}

We can use fancyvrb package, using similar technique as https://tex.stackexchange.com/a/468250/4686

documentclass{article}

usepackage{fancyvrb}

usepackage{framed}

usepackage[dvipsnames]{color}

definecolor{shadecolor}{named}{Goldenrod}



renewenvironment{verbatim}{%

  VerbatimEnvironment

  begin{shaded}

  begin{Verbatim}%

}{%

  end{Verbatim}%

  end{shaded}%

}



begin{document}



begin{verbatim}

la$ la$ la$ la$ la$ la$ la$ la$ la$ la$ la$ la$ la$ la$ la$

la$ la$ la$ la$ la$ la$ la$ la$ la$ la$ la$ la$ la$ la$ la$

la$ la$ la$ la$ la$ la$ la$ la$ la$ la$ la$

end{verbatim}

end{document}

If your fancyvrb version is in the 3.x series but before 3.2 of 2019/01/08 you may need to use this preamble instead:

PassOptionsToPackage{dvipsnames}{xcolor}

usepackage{fancyvrb}% loads xcolor hence option clash hence the above

usepackage{framed}

definecolor{shadecolor}{named}{Goldenrod}

(or load xcolor with dvipsnames option before loading fancyvrb), because for these releases fancyvrb loaded xcolor.

With etoolbox it's quite easy. You can use the BeforeBeginEnvironment and AfterEndEnvironment hooks:

documentclass[12pt]{article}

usepackage{xcolor}

usepackage{framed}

usepackage{etoolbox}



definecolor{shadecolor}{RGB}{200,200,0}

newenvironment{Shaded}{begin{snugshade}}{end{snugshade}}



BeforeBeginEnvironment{verbatim}{begin{Shaded}}

AfterEndEnvironment{verbatim}{end{Shaded}}



begin{document}



begin{verbatim}

text

end{verbatim}



end{document}

or, if you can't add more packages (although, chances are etoolbox was already loaded by another package), you can copy the relevant parts of the code:

documentclass[12pt]{article}

usepackage{xcolor}

usepackage{framed}



definecolor{shadecolor}{RGB}{200,200,0}

newenvironment{Shaded}{begin{snugshade}}{end{snugshade}}



makeatletter

% Copied from latex.ltx

defbegin#1{%

  csname @beforebegin@#1@hookendcsname% <<-- Added this

  @ifundefined{#1}%

    {defreserved@a{@latex@error{Environment #1 undefined}@eha}}%

    {defreserved@a{def@currenvir{#1}%

     edef@currenvline{on@line}%

     csname #1endcsname}}%

  @ignorefalse

  begingroup@endpefalsereserved@a}

defend#1{%

  csname end#1endcsname@checkend{#1}%

  expandafterendgroupif@endpe@doendpefi

  csname @afterend@#1@hookendcsname% <<-- Added this

  if@ignore@ignorefalseignorespacesfi}

% Copied from etoolbox.sty

DeclareRobustCommand{BeforeBeginEnvironment}[1]{%

  expandaftergapptocsname @beforebegin@#1@hookendcsname}

DeclareRobustCommand{AfterEndEnvironment}[1]{%

  expandaftergapptocsname @afterend@#1@hookendcsname}

newcommand{ifundef}[1]{%

  ifdefined#1%

    ifx#1relax

      expandafterexpandafter

      expandafter@firstoftwo

    else

      expandafterexpandafter

      expandafter@secondoftwo

    fi

  else

    expandafter@firstoftwo

  fi}

DeclareRobustCommand{gappto}[2]{%

  ifundef{#1}

    {xdef#1{unexpanded{#2}}}

    {xdef#1{unexpandedexpandafter{#1}unexpanded{#2}}}}

makeatother



BeforeBeginEnvironment{verbatim}{begin{Shaded}}

AfterEndEnvironment{verbatim}{end{Shaded}}



begin{document}



begin{verbatim}

text

end{verbatim}



end{document}

You can use fancyvrb and fvextra:

documentclass{article}

usepackage{fancyvrb,fvextra}



definecolor{shadecolor}{RGB}{200,200,0}



RecustomVerbatimEnvironment{verbatim}{Verbatim}

{highlightlines=1-10000,highlightcolor=shadecolor}



begin{document}



begin{verbatim}

la$ la$ la$ la$ la$ la$ la$ la$ la$ la$ la$ la$ la$ la$ la$

la$ la$ la$ la$ la$ la$ la$ la$ la$ la$ la$ la$ la$ la$ la$

la$ la$ la$ la$ la$ la$ la$ la$ la$ la$ la$

end{verbatim}

end{document}

As far as I can see, there is no way to specify that you want to highlight all lines, so I set 10000 as the last line, which should be sufficient.